This invention relates to interlocking mechanisms for circuit breakers, particularly to a mechanism that opens and prevents closing of a circuit breaker if an external control system is not connected to or is disconnected from the circuit breaker.
When a circuit breaker is controlled by an external operational control system that is connected by a conductor cable to the circuit breaker, it is essential to have the control system connected to the circuit breaker at all times to insure that the control system will function to open the circuit breaker if necessary. Since these control systems typically include over-current sensing, phase sensing, and similar functions that monitor for fault conditions, a means must be provided to insure that the electrical connection is made and functioning.
With this invention an interlocking means is provided for opening the circuit breaker when the control system is disconnected from the circuit breaker. A plug connection connects the control system to the circuit breaker and the removal of the plug moves a cable that moves an arm and operates a trip latch that indicates that the control plug is not in position on the circuit breaker. If the control plug is not connected or is removed, the trip latch position causes operation of a latch mechanism and the circuit breaker either will not operate to close or will open.
The objects and advantages of this invention will be apparent from the following description.